The "full-aircraft" tests are investigating installation effects on the counter-rotating open-rotor engine Snecma is developing under Clean Sky, including pylon and wing-wake interference and flow directivity effects. They follow earlier isolated-engine windtunnel tests.

Both Snecma and Rolls-Royce are developing geared open-rotor demonstrators under Clean Sky's Sustained and Green Engines (SAGE) project. Snecma's SAGE 2 demonstrator is planned for flight testing on a modified A340-600 in 2016 - almost 30 years after General Electric's GE36 Unducted Fan flew on an MD-80 (leading to the still-born MD-91X).Concept: Clean Sky